Jack-in-the-box
One note jumping up and down an octave on every beat. One of the broken chord patterns.
How to play it
Find the notes
Put your left hand over a C chord. You need low E (little finger, 5) and high E (thumb, 1).
Count and play
Count 1, 2, 3, 4. Play low E on 1, then high E on 2, then low E on 3, then high E on 4.
Move it with the chords
When the chord changes to G, the same rhythm moves to the notes of G: low B and high B. Play it slowly over the chord loop above, at 60% speed first, then faster.
Songs that use it
Questions
What is Jack-in-the-box on piano?
One note jumping up and down an octave on every beat. Chord tones one at a time, within an octave. Musicians call it broken chord 3-10.
Is Jack-in-the-box hard to play?
It is a beginner pattern. Play it with your left hand alone at 60% speed until it feels steady, then add the other hand.
Which songs use Jack-in-the-box?
Copycat by Billie Eilish, Marry Me by Train and Merry Xmas Everybody by Slade use Jack-in-the-box. The songs on this page all use it in the left hand, the most played first.